1.3 Density Curves and the Normal
Distribution
Software exists to add a smooth curve to a
histogram
As in the following two examples
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2
Density Curve
A density curve is a curve that
Is always on or above the horizontal axis
Has area exactly 1 underneath

4.4 Means and Variances of
Random Variables
We discover how means and variances can be
calculated for populations described by
discrete probability distributions
Rules are given for calculating means and
variances of simple functions of random
variables
1